Belt conveyor systems are used for bulk material or goods transportation in different industries, such as mining. A conveyor system includes a conveyor belt which carries the bulk material, such as coal or lignite, or the goods, and transports them continuously over a long distance from one point to another. In the mining industries, the belt conveyor systems are subject to harsh environmental conditions which can cause wearing of the conveyor belt material and result in damage of the belt, such as cracks and rips. Such damage does not only reduce the lifetime of the conveyor belt but may also lead to an unexpected stop of production if not recognized in time to organize for the maintenance of the belt. Because the conveyor belt is continuously moving under normal operating conditions, it can be difficult to monitor the condition of the belt and to measure the state of wear and tear or to detect any damage.
In the art, it is known to integrate embedded measuring parts like stress sensors, induction loops or antennas in the conveyor belt material. These embedded measuring parts interact with corresponding contactless receivers for example through wireless communication or via ultrasonic or inductive signals, where the receivers are attached to the mechanical structure of the belt conveyor system.
For example, U.S. Pat. No. 6,047,814 discloses a method for monitoring a continuous moving belt, where two transponders are disposed in or on the belt in the connecting region of the belt, where the connecting region is the region in which the ends of the conveyor belt are connected to each other. The transponders each transmit a signal to an external transmitter/receiver unit when passing through an operating region of the external transmitter/receiver unit. The transponders are integrated circuits which are conductively connected to a coil. The transponders are positioned within the connecting region due to the fact that it was recognized that the connecting region is a weak location in the conveyor belt which should be monitored for signs of loosening.
In DE 10 2008 018 238 A1, a device for the non-destructive detection of an operating state of elastic components, such as conveyor belts made of rubber, is disclosed. In the conveyor belt, elastomer encoders are embedded in two so called measuring regions, where the first measuring region has a different timely behavior of its tensile strength compared to the second measuring region. The device further has a sensor station by which magnetic fields originating from the elastomer encoders can be detected when passing the sensor station, where the magnetic fields are then processed into information about the expansion or elongation of the corresponding measuring region.
The U.S. Pat. No. 4,436,198 describes a conveyor belt rip detection system, where a plurality of antennas is embedded in the belt generally transversely to the travel direction of the belt and where the respective antennas pass in capacitive coupling relation with a transmitter/receiver at a rip detector station and send an electrical signal to the transmitter/receiver. A rip or crack in the conveyor belt material will be recognized through the corresponding antenna being broken and not sending any signal to the transmitter/receiver.
An alternative solution for identifying the condition of a conveyor belt is known for example from U.S. Pat. No. 7,427,767 B2, where a device captures two-dimensional images of successive belt sections. The captured images are transmitted to an evaluation device where the images are compared with reference images and at least one statement about the condition of the belt is determined. The images are captured using either electromagnetic radiation (e.g., visible, infrared or ultraviolet light), or penetrating radiation, such as X-ray radiation.